<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
    <h1>阿基里斯到家啦</h1>
    <button>点击获取用户数据</button>
    <script>

      const btn = document.querySelector('button')
      btn.onclick = function () {
        const xhr = new XMLHttpRequest()
        xhr.open('GET', '/data') //这里满足同源策略, url可以简写 自动加上 协议域名端口
        xhr.send()
        xhr.onreadystatechange = function () {
          if(xhr.readyState === 4) {
            if(xhr.status >=200 && xhr.stauts<300) {
              console.log(xhr.response)
            }
          }
        }
      }






    </script>
</body>
</html>